Research On The Optimization Of Isolator Parameters And Arrangement Of Flexible Floating Raft System

Vibration Isolation is an important mean to reduce the vibration of ship power equipment, it can be divided into passive and active forms. Passive vibration isolation has its advantages such as a simple structure, easy to implement, high reliability. It has been widely used. However, the vibration isolation is poor in the vicinity of the resonant frequency and low frequency. It is difficult to meet the requirements of reducing vibration and noise in many systems. Active vibration isolation can adjust the support characteristics parameters on line according to the control law to meet the requirements of vibration and noise reduction in low-frequency and near the resonant frequency which passive vibration isolation can not be achieved.Vibration Isolation system of ship floating raft develops toward the direction of large-scale and light due to the special requirements. If parts of the system are considered as a rigid body there is a big error with the actual system, and raft body and foundation shall be considered as a flexible body. On this paper the magnetic suspension of flexibility floating raft system is studied, expand the flexibility of raft body'influence on active magnetic suspension isolator and passive isolator parameters and its arrangement, which is very necessary to improve the effect of the vibration isolation system.Active vibration isolator is a key component of implementation of active vibration control. The function of active vibration isolator is to impose control on the object of control in accordance with the control rule. In this project the magnetic vibration isolator is designed, and the rotation of the middle raft and deformation of their flexible will cause armature slope that in the maglev active vibration isolator, thus affecting magnetic force, and also will have a great effects on the control affection of vibration isolation system. In this paper, armature slope' influence on the size of the magnetic force were calculated theoretically, and finite element means were adopted to analysis magnetic slope's influence on magnetic flux density. The results show that the armature slope has great influence on electromagnetic force and magnetic flux density, which need to be amended in the actual control. Dynamic equations were established with more multi-excitation source, multi-layer, multi-freedom vibration isolation system based on flexible base. Numerical analysis method was used to calculate flexible base's influence on the natural frequency of the system, and the isolator stiffness and damping on the basis of the power flow is passed to the impact; It focuses on analysis the influence of the passive isolator arrangement and location on the transfer to the base power flow, and gives the arrangement of the passive isolator rules and optimum proposal.In this paper, multi-excitation source and multi-degree flexible floating raft system of dynamic equations were established by modal method. Considering the rigid foundation, using the force passed to the foundation as the evaluate index, the passive isolator parameters' influence on system natural frequency and the force passed to the base were studied with numerical analysis. It also studied the rules of isolator arrangement, and based on this arrangement the isolator is optimized. The rule is that the optimal arrangement of the isolator is changed with frequency interference signals.